Method of impregnating electric articles



y 1944- J. G. TANDBERG 2,354,074

METHOD OF IMPREGNA'IING ELECTRIC ARTICLES Filed July 1a, 1942;

INVENTOR.

455A T TORNE Y PatentedJul y 18, 1944" UNITED: :STATES';

PATENT Y OFFICE METHOD or mI P h E GNA'rING" ELECTRIC CLES g Y J v i Jolian Gudbrand Tamlberg', Qtockholm, Sweden, assignor to Electrolux Corporation, Dover, Del.,-

a corporation of Delaware Application July 18, 1 9

42, Serial 110451.485

In Sweden June-11, 1941 2 Claims. (Cl. 117-47) The present invention relates to amethod of initially impregnating particularly electrical -devices'such as condensers or windings with an im-' pregnation solution. In previously known methods of this kind for impregnating articles of the above type the latter have first been evaduated,

solution is viscous, it cannot entirely fill the intersticesof the windings. This drawback is elimmated by the method according to the present nvention, in accordancewith which articles to be initially impregnated are boiled first in a liquid having a lower boiiingpolnt than that or the impregnation solution and then boiled in said solution. Benzol is suitable as the liquidoi lower boiling point. The impregnation solution itself may, according-to the invention, suitably-consistof polystyrol dissolved in toluol-xylol.

The accompanying-drawing shows, as an example of an object intended to be impregnated according to said method, a condenser whose insulation layers designated by Hi may consist of mica, whereas the metallic-layers designated by H suitably consist of aluminium foils.

In carrying out the method according to the invention it is suitable first to dry the object to be impregnated, for example a condenser of the kind shown *in the drawing, by subjecting it to polystyrol dissolved in toluol-xylol. 10

' benzol.

v comprising first boiling the unimpfegnated artiheat. Thereupon the object is boiled in a liquid,

such as benzol which has a lower boiling point than the impregnation solution-which it is desired to use. I and'then boiled in an impregnation solutionhaving a higherboiling point than the liquid in which the article was first boiled. As an impregnation solution use may preferably be made of The invention obviously is not limited to the impregnation or condensers, it also being pos-- sible to impregnate according to the invention other objects, such as windingsfor electric machines, for instances motors, generators and the like. l

hat I claim is:

1. The method of initially impregnating hitherto unimpregnated articles having interstices comprising first boiling the. unimpregnated articles in benzol, and then boiling the articles in a solution of polystyrol dissolved in toluol-xylol, said solution having a higher boiling point than t 2. The method of initially impregnating hitherto unimpregnated article having interstices cles in benzol, cooling the articles, and then boiling the articles in a solution of polystyrol dissolved in 'tcluol-xylol. said solution having a. higher boiling point than benzol.

JonAN G DBnANn TANDBERG.

Afterwards, the"'article iscooled v 

